Intermittent Electrical Issue

Discussion in 'Mechanics Garage' started by THRASHED, Dec 21, 2015.

  1. THRASHED

    THRASHED New Member

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    Hoping someone can help me here. I have an 87 Interceptor. I got it used about 6 months ago, it sat for 19 years in a garage under a cover. I went through the carbs, new tires, new chain, new battery. No issues but it now has the following issues:

    Saturday evening bike barely cranked like it had a dead (almost dead) battery. This is the first time since I've owned it that this has happened. I hooked up the charger, set the charger to "start" mode and it fired right up. Ran it around the block, shut it down, started right up. My wife and I went to a friend's house, no issues.

    This morning the bike started right up. Rode to work, after work it started right up. Stopped at the store, same dead battery issue. Push started the bike and rode home. Parked in the garage, shut it off, and it started right up again. Waited a bit and tried again, still started right up.

    Battery is less than 6 months old. When the engine is running and I give it throttle, there is no difference in the brightness of the headlight. I have checked the battery connections and they are tight.

    Thoughts:

    Internal corrosion on a battery cable?
    Prone to intermittent issues like this?
     
  2. nearfreezing

    nearfreezing New Member

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    What kind of battery do you have? Some of the cheaper ones have half-lives on the order of months.
     
  3. Terry Smith

    Terry Smith Member

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    Certainly sounds like a weak battery or maybe low battery output due to corrosion on the earth cable. Given it started well with your charger which I assumed hooked to the battery terminals, the earth strap should be OK so that would point to the battery. In the first instance I would say get a new battery.
     
  4. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    Charging issues are common with the VFR.
    Check for burned connection at the starter relay and fuse block. Also the Regulator is prone to failure but not intermittent issues. Check for evidence of melted connections at the Regulator and at the stator.
     
  5. squirrelman

    squirrelman Member

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    First thing to check would be charging voltage measured at battery terminals with the engine at 5000 rpm.
     
  6. THRASHED

    THRASHED New Member

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    Thanks everyone. It IS a fairly cheap battery. I run a Shorai in my dual-sport, it may be time to invest in one for this bike. Squirrelman, I'll check the voltage tonight, but the intermittent issue seems like it would rule out charging issues. I'll also pull some plastic of and check all connections. Kind of weird, but at least the bike is easy to push start...
     
  7. THRASHED

    THRASHED New Member

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    So here is what I found with my first test.

    All connections were tight.

    Pulled battery, found one cell about 1/2" low.

    Battery tested at 11.46 volts.

    Placed on charger for about two hours, tested at 12.8 volts.

    20 minutes later, tested at 12.45 volts.

    I put the bike back together (commuting in the morning) but I'll check it one more time before I leave.

    Didn't want to upset the neighbors taking it to 5000 rpm tonight, perhaps tomorrow night, but I'm leaning toward the cheap battery I purchased.
     
  8. THRASHED

    THRASHED New Member

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    Squirrelman: 13.26-13.4~ at idle. 13.6~ at 5000rpm. Is that OK?
     
  9. ragincanadian

    ragincanadian New Member

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    There may be something else going on but the battery voltage should DEFINITELY not drop that much in 20 minutes. Try charging it at 20V ~5A for 90-120 seconds, sit for 30 minutes, then charge at a normal rate. The extra voltage might blast off some deposits on the plates and get it working again, maybe not though. Wear goggles, safety first.
     
  10. squirrelman

    squirrelman Member

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    That's on the low end of what's acceptable.
     
  11. THRASHED

    THRASHED New Member

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    Hmm, may be time for a new stator? Any suggestions over here?
     
  12. THRASHED

    THRASHED New Member

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    sorry ragin, missed that. I may try that also.
     
  13. squirrelman

    squirrelman Member

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    Test the AC stator output, should be between about 8 volts at idle and 60+ volts at about 8000 rpm.
     
  14. THRASHED

    THRASHED New Member

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    So I've been pretty busy and haven't done any stator/regulator checks yet. I have been checking the battery voltage. Yesterday morning, before my commute, it was 12.24. When I got home I checked it, 12.04. I put it on a trickle charger for a few hours, 13.8...then 13.79, 13.78 etc every second or so. I let it get to 13.70 and let it sit there. This morning, 12.78. Doesn't seem right to me, more like the battery has an issue. BTW, all acid levels are within range.
     
  15. Knight

    Knight New Member

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    From squirrel's response that the charge voltage was at the low limit, and that the battery was at 12.04 immediately after a ride, those two points seem to reconcile with a low charging rate.

    The battery will drop to its steady state level after charging. It drops very fast at first then can take several days to lose a couple hundredths. Leaving a battery at rest for several days, the final voltage tells the overall life left in it.

    These numbers (peak charge, then drop) look more normal. The charging numbers in your prior post were very low and did not make sense. Unless using a charger several times has revived the battery a bit.
     
  16. squirrelman

    squirrelman Member

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    'snot always about voltage as a weak battery can show good voltage but not have enuff amps. :disturbed:
     
  17. nearfreezing

    nearfreezing New Member

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    If it's easy to push-start and it idles fine and doesn't shut down while you're riding, the problem is the charge state of the battery at rest. This is usually due to a dying battery or a drain to the battery. I'd check the battery current while the motorcycle is off, with the key out of the ignition. If that's ok, then go ahead and replace the battery with a quality one. A cheap battery just isn't worth the headaches it causes and in the long run costs has a negligible cost difference because it must be replaced more frequently.

    The charging voltages you reported are on the low end but suggest the charging system is working ok. If you clean up the charging system connectors, you might get back a few tenths of voltage.
     
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